Comparing the time-integrated data to a simulated distribution. a) Combined distribution of low-energy deviations of 5 individual GRBs assuming a perfect Band function (no deviations present). The extrapolated fit method was used with LET = 25 keV. b) The low-energy residuals of the GRBs in the sample that survived the data cuts (see Sect. 3.5) for LET = 25 keV. The data distribution b) is broadly similar to the simulated distribution a). The data point outside the main data distribution (on the right) is GRB 090902B.